Coordinate-axes meaning

I) consists of two loops symmetrically placed about the coordinate axes.

If the equation of this line, referred to new coordinate axes in the plane area, is written xcos a+y sin a - h=o, (3) R = f f p(h - x cos a - y sin a)dxdy, (4) zR= f fpx(h - xcos a - y sin a)dxdy, (5) yR = f f py(h - x cos a - y sin a)dxdy.

In the Eulerian notation u, v, w denote the components of the velocity q parallel to the coordinate axes at any point (x, y, z) at the time t; u, v, w are functions of x, y, z, t, the independent variables; and d is used here to denote partial differentiation with respect to any one of these four independent variables, all capable of varying one at a time.

(7) For example, in the equilateral triangle of (8) § 28, referred to coordinate axes made by the base and height, = -2 Ra,(3y/h= - 1.

- In many problems, such as the motion of a solid in liquid, it is convenient to take coordinate axes fixed to the solid and moving with it as the movable trihedron frame of reference.